Defects in Perovskite Solar Cells and Their Passivation Strategies

Due to their excellent photoelectric conversion efficiency and low preparation cost, perovskite solar cells (PSCs) have attracted much attention from researchers and developed rapidly in the past decade. However, the stability and efficiency of perovskite photovoltaic devices still need to be improved for their practical applications. It is mainly because the perovskite thin films are inevitably defective to some extent (such as points defects and extrinsic defects), leading to the occurrence of non-radiative recombination (NRR) inside the device and at the interface, which is closely related to the stability and efficiency of perovskite materials. Therefore, exploring reliable passivation strategies is essential to overcome the adverse effects of NRR losses of such point defects. Here, this article summarizes the perovskite solar cells, including the crystal structure and calculations of electronic properties of perovskites, composition, and principles of operation of perovskite solar cells, and more importantly, different passivation strategies, including Lewis acid-base passivation, anionic and cationic passivation, polymer passivation, and alkyl halogen ammonium passivation for the defects involved in perovskite materials. The passivation effects of these strategies and their regulation mechanisms of point defects involving perovskite materials are also presented. We also discuss the intrinsic relationship between crystal defects and device stability and look forward to feasible defect passivation strategy options for future research. To improve the performance and stability of the device and reduce the photocurrent hysteresis phenomenon, it is necessary to reduce the non-radiative recombination (NRR) effectively. Therefore, exploring reliable strategies for the passivation of defects within perovskite is significant and progress has been achieved by several experimental and theoretical studies. In this work, we summarize the perovskite solar cells, including the crystal structure and calculations of electronic properties of perovskites, composition, and principles of operation of perovskite solar cells, and several commonly used passivation strategies.image